The attached patch makes tangling (org-babel-tangle) work
in indirect buffers. Previously it would fail before running
org-babel-post-tangle-hook because indirect have a buffer-file-name
of nil whereas the code was expecting a string in the following
fragment:

(message "tangled %d code block%s from %s" block-counter
                (if (= block-counter 1) "" "s")
	       (file-name-nondirectory (buffer-file-name (or (buffer-base-buffer) (current-buffer)))))


I hope the patch is in the correct format.

Shaun.